Amplitude limiter



1943- K. SCHLESINGER 2,309,258

AMPLITUDE LIMITER Original Filed Feb. 26, 1937 Patented Jan. 26, 1943'AMPLITUDE LIMITER Kurt Schlesinger, Berlin, Germany, assignor, by mesneassignments, to Radio Corporation of America, New York, N. Y., acorporation of Delaware Original application February 26, 1937, SerialNo. 127,894. .Divided and this application February 11, 1938, Serial No.190,001. In Germany March Claims.

This invention which is a division of application No. 127,894, nowPatent No. 2,190,504, dated Feb. 13, 1940, relates to electricaloscillations and more particularly to a device for equalizing theamplitude of such oscillations having a constant frequency butfluctuating amplitude.

The invention is illustrated according to the accompanying drawingshowing a diagram of a connection according to the invention.

The essential part of the device is a double diode ll-which, of course,may be replaced by two simples diodes-having two anodes and 9. directlyor indirectly heated cathode. The anodes are connected via coils l2 andI3 and via the common anode resistance It to the positive terminal of aD. C. source. Resistance H may be adjusted by a slider IS. The coils l2and I3 form a part of transformers I6 and H. To the terminals I9, of theprimary l8 of transformer I 6 are conducted the oscillations to betreated whilst the secondary 2| of transformer I! may be connected to atuned amplifier 22 having output terminals 23, 24.

The operation of the device is as follows:

The current due to the voltage induced by the oscillations in thecircuit formed by the coils l2, l3 and the tube can, in both directions,not surpass the current of the respective anode so that all higheramplitudes are cut away. The height of the remaining constant amplitudesmay be adjusted by means of the slider IS.

The form of the oscillations so obtained is, of course, not longersinusoidal. In order to make them sinusoidal the secondary 2| may beconnected to the tuned amplifier 22.

I claim:

1. A device for equalizing the amplitudes of oscillations of fluctuatingintensity comprising an input and an output transformer, two electronicdischarge paths, and adjustable ohmic resistance and a source of directcurrent, one terminal of the secondary of said input transformer and.one terminal of the primary of said output transformer being connectedrespectively to one of the anodes of said discharge paths. the two otherterminals of said primary and secondary being connected via saidresistance to the positive terminal and the cathode of said dischargepaths to the negative terminal of said source, said two discharge pathsbeing formed by a tube having a hot cathode and two anodes.

2. A device for equalizing the amplitudes of oscillations of fluctuatingintensity comprising an input and an output transformer, twounidirectional current conducting paths each having an input and anoutput terminal, an adjustable ohmic resistance and a source of directcurrent, one terminal of the secondary winding of said input transformerand one terminal of I the primary winding of said output transformerbeing connected respectively to a corresponding terminal of eachuni-directional current conducting path, the other two terminals of saidprimary and secondary transformer windings being connected serially withsaid resistance and source of direct current to the other terminal ofsaid uni-directional current conducting paths.

3. In combination, a resistor, an electron discharge device having acathode and a pair of anodes, means for supplying alternating currentoscillations between a first of said anodes and said cathode throughsaid resistor, an output circuit connected between a second of saidmeans to rectangular wave form in said output circuit, said last-namedmeans including means for producing a unidirectional potential dropacross said resistor.

4. In combination, a pair of unidirectionally conducting circuits, eachincluding a coupling device common thereto and a source ofunidirectional potential, said source being so poled in each of saidcircuits as to cause current to flow in each of said circuits throughsaid coupling device in the same direction, a source of variablealternating electromotive force connected in one circuit, a load deviceconnected in the other circuit, said source of alternating electromotiveforce increasing current in the unidirectional circuit in which it isconnected during one-half cycle and reducing it to zero during the otherhalf cycle, whereby by reason of the coupling of said coupling devicethe current in the other of said circuits is increased to apredetermined maximum when the current in the first circuit attains zeroand the current in the other circuit is reduced to zero by reason of theunidirectional conductivity of said circuit when the current in thefirst circuit is maximum, the current in said load device being thuslimited in magnitude to predetermined values during both half cycles ofsaid alternating electromotive. force.

5. In combination with an electric system from which it is desired toeliminate voltages having a value higher than a predetermined voltage, atube having a cathode and an anode that is normally positive withrespect to the cathode, means for transmitting negative halt-wavecurrents in the system through the tube in the direction from the anodetowards the cathode, means for rendering the anode negative with respectto the cathode upon the occurrence in the system of a voltage higherthan the predetermined voltage, and means for rendering the renderingmeans independent of the magnitude of the predetermined voltage.

6. A static eliminator having, in combination with a receiving systemprovided with a signalreceiving portion and a signal-delivering portion,a tube having a cathode and an anode and connected with the receivingsystem so that signals received by the signal-receiving portion shall betransmitted through the tube in the direction from the cathode towardsthe anode for a positive half wave and from the anode towards theoathode for a negative half wave to the signal-delivering portion, meansfor maintaining the anode positive with respect to the cathode to adegree less than the voltage corresponding to the static to beeliminated from the signals, and means for maintaining the said degreeindependent of the average magnitudes of the signals.

'7. In combination with an electric system from which it is desired toeliminate voltages having greater than an undesired magnitude, two meanseach having a negative terminal and a positive terminal, means forimpressing upon the said respective two means voltages of substantiallythe said magnitude but of opposite polarity, means for transmitting thesaid voltages through one of the said two first-named means in thedirection from the negative terminal toward the positive terminal for apositive half-wave and from the positive terminal toward the negativeterminal for a negative half-wave and through the other of the said twofirst-named means in the direction from the negative terminal toward thepositive terminal for a positive half-wave and from the positiveterminal toward the negative terminal for a negative half-wave, andmeans for rendering the positive terminals negative with respect to thenegative terminals upon the occurrence in the system of a voltagecorresponding to the undesired voltage.

8. In combination with an electric system from which it is desired toeliminate voltages having greater than an undesired magnitude, two meanseach having a negative terminal and a positive terminal, means forimpressing upon the said 7 respective two means voltages ofsubstantially the said magnitude but of opposite polarity, means fortransmitting the said voltages through one of the said two first-namedmeans in the direction from the negative terminal toward the positiveterminal for a positive half-wave and from the positive terminal towardthe negative terminal for a negative halt-wave and through the other ofthe said two first-named means in the direction from the negativeerminal toward the positive terminal for a positive half-wave and fromthe positive terminal toward the negative terminal for a negativehalf-wave, and

means for maintaining the positive terminals positive with respect tothe negative terminals to a degree less than the voltage correspondingto the undesired voltage.

,9. Apparatus for eliminating undesired peaks from signal voltageshaving, in combination, means for establishing a current in onedirection along a predetermined path to render the path conducting; withthe potential established by the current varying from positive tonegative from one end of the path to the other end of the path in thesaid direction, means for transmitting the signal currents along thepath between the said ends in the opposite direction, means formaintaining the difference of potential between the said ends 01' thepath at a value less than the voltage corresponding to the peaks to beeliminated from the signals, and means for maintaining the said valueindependent 01' the magnitude of the signals.

10. Apparatus for transmitting voltages not greater than voltages ofpredetermined magnitude and suppressing voltages greater than the saidmagnitude having, in combination, two rectifiers each having an anodeand .a cathode, means for impressing upon the rectifiers voltages ofsubstantially the said magnitude but of opposite polarity, means fortransmitting the said voltages through one of the rectiflers in thedirection from the anode to the cathode and through the other rectifierin the direction from the cathode to the anode, and means for renderingthe anodes positive with respect to the cathodes upon the occurrence ofa voltage of the said magnitude.

KURT SCI-ILESINGER.

